<?php
/**
* This file is part of the upgrade process.
*
* @package SendStudio
*/

/**
* Do a sanity check to make sure the upgrade api has been included.
*/
if (!class_exists('Upgrade_API', false)) {
	exit;
}

/**
* This class runs one change for the upgrade process.
* The Upgrade_API looks for a RunUpgrade method to call.
* That should return false for failure
* It should return true for success or if the change has already been made.
*
* @package SendStudio
*/
class queues_unsent_fk_check extends Upgrade_API
{
	/**
	* RunUpgrade
	* Runs the query for the upgrade process
	* and returns the result from the query.
	* The calling function looks for a true or false result
	*
	* @return Mixed Returns true if the condition is already met (eg the column already exists).
	*  Returns false if the database query can't be run.
	*  Returns the resource from the query (which is then checked to be true).
	*/
	function RunUpgrade()
	{
		$constraint_name = 'queues_unsent_recipient_fkey';
		if ($this->ConstraintExists('queues_unsent', $constraint_name)) {
			if (SENDSTUDIO_DATABASE_TYPE == 'mysql') {
				$query = "ALTER TABLE " . SENDSTUDIO_TABLEPREFIX . "queues_unsent DROP FOREIGN KEY " . SENDSTUDIO_TABLEPREFIX . $constraint_name;
			}
			if (SENDSTUDIO_DATABASE_TYPE == 'pgsql') {
				$query = "ALTER TABLE " . SENDSTUDIO_TABLEPREFIX . "queues_unsent DROP CONSTRAINT " . SENDSTUDIO_TABLEPREFIX . $constraint_name;
			}
			$res = $this->Db->Query($query);
			if (!$res) {
				return false;
			}
		}
		return true;
	}
}
